Dynamo-electric machinery.



No. 687,992. Patented Dec. 3, |9l.

A. cHuncHwAnn.

DYNAMO ELECTRIC MACHINERY.

Application led Dec. 18, 1899. Renewed Aug. 14, 1901.)

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UNITED STATES 4PATENT OFFICE.

ALEXANDER CHURCHWARD, OE CHICAGO, ILLINOIS, AssIeNOR To GENERAL ELECTRICCOMPANY, A CORPORATION OE NEw YORK.

DYNAMO-ELECTRIC MACHINERY.

SPECIFICATION forming part of Letters Patent No. 687,992, dated December3, 1901.

Application tiled December 18, 1899. Renewed August 14, 1901. Serial No.72.055. (No model.

T @u Wfl/07W may @Wwefvf separately and slip them over the poles in theBe it known that I, ALEXANDER CHURCH- many cases where the free end ofthe pole is WARD, a citizen of the United States, residing also enlargedoriianged and generally inat Chicago, in the County of Cook and Statecreases the cost of Construction in any case.

5 of Illinois, have invented certain new and Thepresentimprovementcontemplates the 55 useful Improvements inDynamo-Frames, of use of separate detachable pole-pieces bolted whichthe following is a specification. to the frame in such manner as to meetall re- This invention relates to improvelnents in quirements as tolarge Contact area, but withthe frames or field-castings ofdynamo-elecout the use of enlarged base-flanges, which ro tricmachinery, and has for its object to prowould prevent the iield-coilsfrom being slip- 6o vide an improved composite cast and wrought ped overthe pole af terbeing separately wound. iron or steel construction forpossessing both To this end I secure to the frame orfield-castelectrical and mechanical orstructural advaning at the pointswhere the poles lead off tages over the previous art in this line. It isplates of wrought-iron or steel properly prowell known that cast-ironyokes or lields give portioned to afford the necessary area of con- 65the best results in the matter of regulation, tact with the cast-ironand then bolt said are cheaper, more easily worked, and make pole-piecesdirectly to these plates. Being of more perfect Castings. Thepermeability of substantially the same degree of permeability,Cast-iron, however, is not high enough to warthe lines of force willpass between the poles zo rant its use in many cases for thepole-pieces, and plates without undue loss and will also 7o which arebetter made of wrought or lamipass Without undue loss between the platesnated iron or cast-steel of higher permeabiland the cast-iron yoke orfield-frame owing ity; but when such poles are used in connecto a largearea of Contact between them. At tion with cast-iron frames oryokesprovision the same time the removability of the poles must be made foran area of Contact at the enables the field-coils to be wound independ-75 juncture of the pole-piece with the yoke or ently of the poles andthen placed upon or held-casting much greater than the area of removedfrom them without difficulty whenthe pole-piece, it being clear that ascast-iron ever found desirable. is practicallysaturated at fty thousandlines In the accompanying drawings, Figure l 3o of force per squareinch, while wrought-iron shows in side elevation a section of a frame or8o or steel does not become saturated at much yoke of a dynamo-electricmachine provided less than twice that amount, an area of conwith myimprovement. Fig. 2 is a similar tact between the two materials equal toabout view of a construction slightly modified from twice the area ofthe wrought-iron must be that shown in Fig. l. Fig. 3 is a side eleva- 35 provided in order not to overtax the capacity tion of a rotaryfield-Casting with its poles ap- 85 of the cast-iron. By present methodsthe plied in accordance with my improvement. pole-pieces are often castinto the yoke or As shown in Fig. l, A designates the castframe; butthis is not always satisfactory, as iron yoke or iield-frame section,and B its the joint between cast-iron and wrought-iron wroughtorlaminatediron or steel pole-pieces.

4o or steel cast into it is liable to be so poor as The latter areremovably secured to the yoke 9o to require an excessive amount ofcopper to in any suitable manner, as by bolts b, and are force themagnetism through it and as it is herein shown as provided at theirinner or .frequently desirable to be able to remove the free ends withflanges b to prevent any possipoles from the frame or yoke forconvenience bility of the field-Coils slipping off them when in shippingand in erecting or repairing. It applied in the usual manner. 95 is alsocustomary to bolt separate pole-pieces C designates the wrought -iron orsteel to the yoke or frame and provide the increased plates which areinserted between the yoke area of Contact by an enlargement or llangeAand poles B. These plates are made of any at the base of thepole-piece. This, however, suitable shape and of such dimensions as to5o renders it impossible to wind the field-coils afford an ample area ofContact with the cast- Ioo iron yoke. They are secured to the yoke bysuitable bolts or screws c, and the clamping of t-he pole-pieces by thebolt b also serves to hold the plates in close contact with the yoke orframe, as Well as to hold the pole-pieces securely seated against saidplates. The contacting surfaces ofthe frame,plates, and poles are trnedoff by planing orby boring and turning to afford a fair bearing againsteach other, and the eld-coils are conveniently wound separately andslipped over the poles before the latter are clamped in place. Byremoving the bolts l) the poles and coils may then be repaired orreplaced, as desired.

In Fig. 2 the flanges b (shown at the free ends of the poles in Fig. l)are omitted, so that the field coils could be slipped over them withoutremoving the poles from the yoke; but even in this case my improvedconstruction is desirable. In Fig. 3 a rotary field-casting ct is shownas provided with pole-pieces Y B', which are bolted to Wrought-iron orsteel I claim as my invention n l. The combination with thefield-casting or frame of a dynamo-electric machine, of Wrought-iron orsteel plates secured to said frame,Wrought-iron or steel pole-piecesseated against said plates, and means for securing the pole-piecesremovably in position on said plates, substantially as described.

2. The combination With the Held-casting or frame of a dynamo-electricmachine, of Wrought-iron or steel plates bolted to said frame orfield-casting, wrought-iron or steel pole-pieces seated against saidplates, and bolts applied between the frame or field-casting and thepole-pieces and passing through the plates to clamp the pole-piecesremovably to the frame or field-casting with the plates intervening,substantially as described.

In testimony that I claim the foregoing as my invention I afiix mysignature, in presence of two subscribing Witnesses, this lith day ofDecember, A. D. 1899.

ALEX. OI-IURCHW'ARD.

Witnesses:

HENRY W. CARTER, ALBERT H. GRAVES.

